The wideband power amplifier (PA) is the key component in the wideband transmitter (TX). Currently a lot of wideband PA design solutions are used such as distributed amplifier, balanced amplifier, high-order output matching amplifier and tunable amplifier. Multiple inductors for the inter-stage/output-stage matching and tunable matching network with low quality-factor are in sacrifice of power efficiency for such PAs, respectively.
Back-off efficiency of available PA designs is poor even when using an output matching network such as a dual-modes matching network or even a multiple modes matching network. There is a need to provide a design concept for a wideband power amplifier or TX with high back-off efficiency.